just informed myself about diamond dependency problems, i.e. the problem when a package A depends on package B and C which both depend on another package D, however with different versions. I.e. package B uses D v1.2 and C uses D v1.3. The crux in such a setup is that you cannot easily pass results…

At any given moment, you only have one “virtual environment” active. The requirements of A will determine the versions of B and C, and their requirements will in turn determine the version of D. In your example, C requires D v1.3 and so this is the version of D to be installed, not the older version…

just to mention the only reference I found about julia and diamond dependencies: https://news.ycombinator.com/item?id=17719489 (but as you see, there is only the question, without an answer)

This can never happen; there can only be one version of D.

Thanks for your answer, can you please elaborate? What am I overlooking? How should it be impossible for package B and C to use different versions of D? They have their own “virtual environments” (in Python terms) and can use whatever they want to

Spot on. I also believe @schlichtanders may be misunderstanding how Python virtual environments work. You can have different versions of D in different environments but only one environment is active for a given Python process—virtual environments are implemented by manipulating various environment …

[image] StefanKarpinski: Note that the “dreaded diamond dependency problem” is not all that dreaded in dynamic languages. This is because dynamic languages can fairly easily perform load time reflection to work with different incompatible APIs for different versions of dependencies. This soun…

Julia packages program around API differences all the time. Compat for example provides a consistent API across many underlying Julia versions by checking the Julia version and implementing the consistent API in terms of whatever Julia version is running. This is one of the reasons why Julia version…

That’s a great example. Thanks!

How does the julia 1.0 Pkg handle diamond dependencies?

General Usage

Sukera January 13, 2019, 12:07pm 6

See here for some more info.

Topic		Replies	Views
Multiple Versions of one Module in same Environment General Usage	3	719	September 20, 2018
Independent version requirements for each dependency to avoid downgrades? General Usage	18	1270	October 3, 2021
Different versions of same package in dependency graph General Usage dependencies , package-management	4	489	May 30, 2022
Is any way to install multiple versions of same package? General Usage	4	3095	February 17, 2019
Julia version dependency of a dependency New to Julia packages , dependencies	4	690	August 24, 2020

How does the julia 1.0 Pkg handle diamond dependencies?

Related topics